Take Over
by JustThoseGuys
Summary: Space Marine AU. They had all been looking foward to a little bit of downtime after the last mission, Theo included. Now, he feels pretty confidant that he would have much rather stayed on a mission forever. After all, coming home to a guerilla war isn't on anyone's bucket list, but now it'll take every bit of Theo's training to make it through this one alive.


**Chapter One: Home is Where the Heart Is**

The clang of titanium boots rang clearly down the corridor. Dim, red emergency lights shone overhead, casting long shadows as a singular armored man slid to a halt, turning to face multiple pursuers. With a quick draw, his personal sidearm raised to eye-level with a tremble and rang with the sound of multiple shots. Each bullet headed toward to the leader of the pack behind him, only to be deflected by a charge-blade.

Return fire by the remaining group members clipped his pauldrons, leaving scores across his CREST model body armor. A quick survey led him to aim at a nearby hydraulic pump, and soon the hiss of superheated steam covered his quick exit down another passage. The scream of a scalded enemy might have bought him a couple of seconds, but the rest of the pack would be quick to pursue him. At the end of the hallway, the bright expanse of a freezing blizzard outside spurred his movements to be a little faster. A quick trigger pull later, and the panel next to the blast door went haywire from the bullet currently resting in the wiring.

At this moment, the group behind him rounded the corner, and the rapid staccato of rifle shots pinged around him. The door ahead of him was slowly dropping down, nearly halfway from trapping him in a metal tomb. More bullets whizzed around him, and one grazed his lightly armored calf. With a cry and a momentary stumble, he lunged forward while his armor thrusters fired, managing to slide under the door just before it shut.

The negative 40 degree temperatures treated his body no kinder than the bullets, and while his suit's life support worked overtime to keep his body temperature regulated he frantically searched for a different entry point to the compound. The longer he spent outside, the faster his body began to slow down, increasing his chances of ending up as another block of ice. Just when he thought his joints had frozen stiff, he stumbled across an emergency hatch to the compounds ventilation system. He managed to pry it open with a pained effort, and he dropped down into the much more manageable environment.

He laid back against the wall of the nearby ventilation shaft, too exhausted to go any further and momentarily safe from his pursuers. With a pained groan, he pried off the greaves from his armor, revealing a gash down the back of his legs. He pulled off the basic first aid kit hooked to the back of his armor, and quickly went to work on his injury. Once he'd finished cleaning the wound and wrapping it with sterilized bandages, he laid back to finally catch his breath.

He hated the recycled air being fed through his suit's ventilation system, and reached up to his helmet fastenings. Several sharp clicks sounded, and the armored man's helmet slowly disconnected with a hiss, unclasping from the rest of his armor to reveal green locks and amber eyes. The pain in his leg now dulled to manageable levels, Theo Cornaro could no longer fight off his fatigue and laid his head back before losing consciousness.

 ** _XTOX_**

 _Theo finished stitching the cut on Lassic's arm, the burly engineer having come up from the engine room after patching up a stray hitch in the system. The last tug drew a small grunt of discomfort from his patient before he clipped the string short and tied it down._

" _Oi, careful now Theo! I gotta have both arms if I wanna keep this ship running!" Lassic exclaimed with a quick laugh._

 _The team medic just rolled his eyes with a smirk, used to his crew member's banter. "Maybe if you didn't break everything you touched, you wouldn't have to fix it and get yourself cut up."_

 _The bigger man just laughed. "Maybe you guys should stop running this ship ragged and finally pony up for a new one from the Union."_

 _The easy going conversation continued as Lassic led Theo out of the medbay towards the bridge, passing by a couple of other crew members. Once on the bridge Lassic left the team medic to talk to Navigator Moreno Dortous, the two friends bickering like always. The team medic and acting XO came up to the captain deep in thought near the large frontal viewport. Theo took in the frosty moon in front of him, near the size of Earth, and the large colored bands of Jupiter in the background before breaking the silence. "Sir?"_

 _A little more time passed before the captain, Villar Constance, turned to him. "Hello, Theo. How is Engineer David?"_

" _Doing just fine, sir. Just a small cut caused by his own negligence. He's ready for planetside anytime you need," Theo said._

 _Constance turned back to the view before him, his features relaxing a tad. "Good. It's always better for the crew to be a full strength. Are you ready to stretch your legs a bit? We're almost to base Unicorn."_

" _Always, sir," Theo replied._

 _Nothing else was spoken as the Artuk made its descent towards the compound hidden in the snow below. Theo tuned out the background chatter and enjoyed the peace and quiet as they touched down inside the compounds landing pad._

 _Theo and Villar made their way down the loading ramp of the Artuk, somewhat surprised by the lack of a welcoming party. For Theo, it didn't mean much, seeing as the compound was generally undermanned whenever the crew went on missions. The lack of respect for even one person to meet with them stung a small amount, but in the end he brushed it off. That was before multiple rockets fired into the Artuk, blowing it to hell and launching Theo and the rest of the landing crew to into the surrounding area. Theo's last conscious moment was Villar dragging him into a nearby hallway, and watching several armor clad figures converge on his downed crewmates._

 ** _XTOX_**

Theo startled awake, tormented by the nightmare of the previous hour. Slowly, he leaned his head forward into his hands, all of tension pent up in his body being released in shuddering breaths.

 _Honestly, I don't know what else could go wrong at this point._

Earlier it had been him and Villar together. Once he had woken up, he and Villar managed to retrieve their sidearms and CREST suits from the wreckage of the _Artuk,_ but by that point their crew members were gone. It didn't help matters that the mysterious enemy they faced had set up a watch on the ship, and Villar had drawn their attention so that Theo could escape.

The combat medic would have made it away clean, if not for a stray patrol that had responded to the call from the team stationed at the ship. Because of this series of events, Theo found himself alone, in an air duct, with a mostly healed leg in what was suddenly enemy territory.

Eventually, his silent sobbing soon came to an end, replaced by calm determination. Theo began re-attaching his leg armor and his helmet while running through what he knew.

 _Crew still alive? Unknown._

 _Villar still alive? Probably, but Unknown._

 _Enemy identity and strength? Unknown and unknown._

 _Compound layout?_ Theo ran a quick check for the full schematics on his armor's built in wrist pad, and before long a complex floor by floor map showed up.

 _Check. Camera access?_ The wrist pad brought up a negative this time. _Not currently, but if I find an engineer's access panel then I can rectify that._

 _Step one? Find friends, and find out what I'm up against._

Theo, ignoring the lingering discomfort in his leg, began marching through the large air shafts that regulated the compound's temperature. Taking out a ration bar from the first aid pack, his faceplate slid back to let him much on it while scanning the map on his wrist.

 _The most likely place for prisoners to be is in the cell block next to the command center. Searching there first could be my chance to kill two ships with one railshot._

With a destination in mind, Theo navigated his way towards the northern section of the base. The base layout was easy to remember, and was burned in his mind from his time serving in under captain Villar. Crew dormitories and armories were located in both east and west sections, and the aforementioned command center and cell blocks resided in the northern sections. The northeast and northwest sections contained training courses and extra dormitories for officers. The mess hall was situated in the dead center, connecting each of these wings and the southern section of the base, where all manner of transportation were tended to.

The knowledge of his surroundings would have been a great boon—if only Theo could safely travel throughout the base itself. He cursed inwardly at his lack of knowledge regarding enemy movements and patrols, and the labyrinth-like layout of the ventilation system. His current method of travel could only lead him vaguely northward, not directly to where he wanted to go.

A silent half-hour of travel ended fruitlessly, having nearly made his way above where he wanted to go only to be cut off by a giant, violently whirring fan. While he appreciated the work it did in keeping the bone-numbing cold outside, Theo couldn't help but growl in frustration. He needed to find his crew, dang it!

With nothing left to do but backtrack to find a different route, he slowly made his way back down a different path to the mess hall. Just when he was going to break off down a different pathway, he heard sounds coming from back toward the mess. Theo creeped his way toward the nearest grate, and peered through to see below. The commotion he heard sounded louder than before, and definitely seemed like some sort of fight, but he still wasn't close enough to see it. A small group of enemy soldiers rushed below him through the mess toward the eastern dormitories, and the sounds of scuffle moved farther away in that direction.

Theo waited a few moments to see if any further troops were coming, then quickly removed the the grate under him. Dropping down with a quiet grunt, he stalked his way through the mess towards the east wing. As he made his way through the base, having to stop and hide in a nearby supply closet one time to let another patrol pass by, Theo could hear the confrontation ever louder.

It was coming from the next hallway, where the dorms were connected.

 _Smart. Narrow corridors means less opponents to fight at a time._

While he could appreciate the tactics of his potential ally, he didn't have time to waste. Rounding the corner, Theo ran into several bodies, which upon closer inspection, bore the symbol of the Deep Space Alliance.

 _What is the DSA doing here? We just recently signed a ceasefire agreement not six months ago._

Frowning for a moment, Theo resolved to let the mystery lie until he and his friend managed to get out of the current situation. He came up quietly behind the struggle, just in time to see Captain Villar take a bad slash on the arm.

Make no mistake, his opponents were the same group of soldiers who chased Theo previously. The wielder of the charge blade now lacked a helmet and several pieces of armor, revealing a woman with purple hair and branching red tattoos.

 _A Valkyrie? It would explain how she could deflect my bullets…_

It was clear that Villar was exhausted and injured, fighting with his own charge blade since his sidearm must have ran dry long ago. Theo could see only one way for them to come out potentially unscathed, seeing as he didn't have a chance in melee combat against the Valkyrie. The other soldier in the pair was hanging back, nursing a slash wound on her now limp arm.

Having come upon them unnoticed, Theo drew his sidearm before pistol whipping the injured one and taking her as a hostage. The blow knocked off the soldier's helmet, revealing a younger blonde woman. He held the blonde soldier in a chokehold, pistol aimed directly on her temple before shouting to garner attention.

"Hey!"

The Valkyrie shoved Villar against the back wall before whipping around to face him, and her eyes went wide.

Theo, stone-faced, said, "An even trade. Your comrade's life for ours. Walk out into the other hallway, and she's yours."

The Valkyrie said nothing in response, but the clench of her fists and the fire in her eyes said enough. Slowly but surely, she worked her way back into the adjacent corridor, Theo following at a safe-distance with the still dazed woman in his grip. Once they had reached the end of the passage, she turned, smirking at him.

His temporary confusion soon morphed into frustration as he grit his teeth, hearing the footsteps of her backup coming in fast. Thinking fast, he shot the door panel, and as it started to close he tossed his captive out through the door into the Valkyrie, giving the door enough time to shut before she could intervene.

Quickly, now that they had a reprieve, he rushed back to Villar's side, who was now sitting on the floor against the wall.

"Captain! Are you okay?" Theo asked while checking the extent of his injuries.

Villar tensed as the injuries he sustained through the fight began to come back to him. "Not good XO. I evaded the guards chasing me, only to get myself stuck trying to reach one of the armories." He let out a pained laugh before breaking down into coughing.

Theo immediately grabbed some painkillers out of his pack before saying, "Hey, save your strength. We're gonna find a way out of here and save the others."

Villar smiled and nodded at that, and took the painkillers. They were both cut off from their thoughts, however, when a loud crackling sound came from down the hall. Theo rushed out to see the slow progress of a flame cutter burning through the door.

He ran back to tell Villar, "We've got a problem. They're cutting through the door."

Villar grimaced, "Not good. We're trapped."

A moment passed where Theo looked at his wrist pad, and he quickly spoke up, "Maybe not. I got this far coming through the ventilation shafts, and according to these schematics each dorm has an air duct that connects to it."

Theo looked around the room they were in, and located the nearest grate in the center of the room. He dragged one of the bunk beds under it before helping Villar up on top of it, the sounds of the metal being burnt apart growing louder by the second.

Finally he managed to get the grate cover off, and pushed Villar up into the air duct at the same time that a crash of metal occured down the hall. Before climbing up after him, he used one of his last remaining bullets to shoot the door panel, buying them a little more time to escape before the enemy learned where they had escaped to.

After replacing the grate, he found Villar painfully walking away from where they entered. "We need to—gah‒—get away from the entry point. We, ghhhh, might have some time, but—," At this point, the captain's injuries proved too much as his body gave way. The loud thump of his body hitting the floor echoed on, as did the pained cry that escaped his lips.

Theo appeared at his side in an instant, saying calmly, "Your body is too weak right now. Please rest and let me have a look at you."

The pain being to much to handle, Villar simply nodded. Now that Theo had ample opportunity, he could see that his captain took quite the beating. Besides the large gash on his arm, there were numerous bruises and cuts maring his body. Once his examination reached the torso, things took a turn for the worst. The scarred CREST armor had held true against most of the bullets, but between the plates the protection was thinner. Between two abdominal plates, a small bullet wound made itself known.

"Captain. Can you do me a favor?" Theo said as he pull out a strip of gauze and a flask.

"Wh… what is it?" Villar huffed out.

Theo placed the cloth in his mouth. "Bite down. Hard."

Theo cut apart the material between plates before applying a generous dose of alcohol to the wound. The captain under him screamed through his teeth while the alcohol cleaned the would. He rolled the captain over, performing the same procedure on the other side on the exit wound, before taking the last two bullets out of his pistol's magazine.

Now that the easy part was done, he needed to cauterize the wound. Theo had no way of limiting the bleeding before the captain gave out, so he had to do the next best thing and stop the bleeding all together. He pried the back end of the first bullet off, and dumped a small amount of gunpowder into the entry point. Taking out a couple of matches from the first aid kit, he proceeded to light the gunpowder on fire.

By this point, Villar had lost consciousness. Theo's face scrunched up as his moved to repeat the procedure in the back with the second bullet.

 _C'mon captain. You'll pull through. I know you will._

He wiped his hands on the pants of his suit, moving to clean and bandage the wound on his arm now that the most life-threatening injury had been treated. It took a few minutes to treat the rest of Villar's minor injuries, but Theo could tell the adage, 'death by a thousand cuts,' had merit.

Theo sighed to himself. _Nothing I can do now but set up camp._

Taking the unconscious captain in a fireman's carry, he slowly made his way a good distance into the maze of ventilation shafts, in a spot between two different shafts. He laid out the captain as gently as he could, hoping to let him be comfortable. Having nothing to set traps with, nor any bedding with which to cover the captain, Theo decided to replace the captain's bandages and get some rest. He settled down on the opposite side of the shaft, his first aid pack under his head, and eventually drifted off into an uneasy sleep.

* * *

 **AN: Hey there. Binge watched the entirety of Grancrest Senki up until Episode 14, and I had a little idea. I'm not sure if this is going to go anywhere, but I've got some ideas for the future and we'll see what happens.**


End file.
